[Answered] Should I Use Comma Before 'Either' in This Scenario?

[mnattw]

"I wish to work as a dental specialist, either an endodontist or a prosthodontist."

My friend suggested taking out the comma before 'either'.
Is he right? Why?

 

[Barb_D]

The comma belongs there. The part that comes after is explaining what you meant by "dental specialist" and should be set apart from it with a comma.

 

[Matthew Wai]

"I wish to work as a dental specialist, either an endodontist or a prosthodontist."

I take it to mean 'I wish to work as a dental specialist, who can be either an endodontist or a prosthodontist', where the relative clause is non-restrictive, so a comma is needed before it.